The UK energy regulator, Ofgem, has announced that the UK energy price cap will rise in October by an average of 2%. The energy price cap sets the maximum prices for electricity and gas that can be charged by suppliers to households. For those paying by direct debit, the maximum electricity price per kilowatt-hour (kWh) will rise from 25.73p to 26.35p, with the maximum daily standing charge rising from 51.37p to 53.68p. As far as gas is concerned, the maximum price per kWh will fall slightly from 6.33p to 6.29p, with the maximum daily standing charge rising from 29.82p to 34.03p. Ofgem estimates that this will mean that the capped cost to the average household will rise from £1720 to £1755.
The average capped cost is now much lower than the peak of £4279 from January to March 2023. This followed the huge increase in international gas prices in the aftermath of the invasion of Ukraine and the cutting off of gas supplies from Russia. Note that although the suppliers received these capped prices, average consumers’ bills were limited to £2500 from October 2022 to March 2024 under the government’s Energy Price Guarantee scheme, with suppliers receiving a subsidy from the government to make up the shortfall. But despite today’s cap being much lower than at the peak, it is still much higher than the cap of £1277 prior to Russia’s invasion of Ukraine: see Chart 1 (click here for a PowerPoint).
So is the capped price purely a reflection of the international price of gas, or is it more complicated? The picture is slightly different for gas and electricity.
Gas prices
As far as gas prices are concerned, the price does largely reflect the international price: see Chart 2 (click here for a PowerPoint).
The UK is no longer self-sufficient in gas and relies in part on imported gas, with the price determined in volatile international markets. It also has low gas storage capacity compared with most other European countries. This leaves it highly reliant on volatile global markets in periods of prolonged high demand, like a cold winter. Is such cases, the UK often has to purchase more expensive liquefied natural gas (LNG) from global suppliers.
Additionally, taxes, environmental levies and the costs of the nationwide gas distribution network contribute to the overall price for consumers. Changes in these costs affect gas prices. These are itemised below in the case of electricity.
With electricity pricing, the picture is more complex.
Electricity prices
Electricity generation costs vary considerably with the different methods. Renewable sources like wind and solar have the lowest marginal costs, while natural gas plants have the highest, although gas prices fluctuate considerably.
So how are consumer electricity prices determined? And how is the electricity price cap determined? The price cap for electricity per kWh and the daily standing charge for electricity are shown in Chart 3 (click here for a PowerPoint).
Marginal cost pricing. The wholesale price of electricity in the UK market is set by the most expensive power source needed to meet demand on a day-by-day basis. This is typically gas. This means that even when cheaper renewables (wind, solar, hydro) or nuclear power generate most of the electricity, high gas prices can increase the cost for all electricity. The wholesale price accounts for around 41% of the retail price paid by households.
It also means that profits for low-marginal-cost producers could increase significantly when gas prices rise. To prevent such (low-carbon) suppliers making excess profits when the wholesale price is high and possibly making a loss when it is low, the actual prices that they receive is negotiated in advance and a contract is signed. These contracts are known as Contracts for Difference (CfDs). CfDs provide a fixed ‘strike price’ to low-carbon generators. The strike price is set so as to allow low-carbon generators to recoup capital costs and is thus set above the typical level of marginal cost. If the wholesale price is below the strike price, payments to generators to cover the difference are funded by amounts collected from electricity suppliers in advance using the CfD Supplier Obligation Levy. If the wholesale price is above the strike price, the difference is returned to consumers in terms of lower electricity bills.
Policy costs. Electricity bills include an element to fund various social and environmental objectives. This element is also included in the cap. From October to December 2025, this element of the cap will be 11.3%. The money helps to subsidise low-carbon energy generation and fund energy efficiency schemes. It also funds the Warm Home Discount (WHD). In the October to December 2025 price cap, this amounted to a discount for eligible low-income and vulnerable households of £150 per annum on their electricity bills. The WHD element is included in the standing charge in the price cap. From October 2025, more generous terms will mean that the number of households receiving WHD will increase from 3.4 million to 6.1 million households. This is the main reason for the £35 increase in the cap.
Network costs. These include the cost of building, maintaining and repairing the pipes and wires that deliver gas and electricity to homes. From October to December 2025, this element of the cap will be 22.6%.
Supplier business costs. These include operating costs (billing, metering, office costs, etc.) and servicing debt. From October to December 2025, this element of the cap will be 15.4%.
Profit Allowance. A small percentage is added to the price cap for energy suppliers’ profits. This is known as the Earnings Before Interest and Tax (EBIT) allowance and is around 2.4%. This has a fixed component that does not change when the overall price cap is updated and a variable component that rises or falls with changes in the cap.
Reliance on gas, low gas storage facilities, marginal cost pricing and the commitment to invest in low-carbon electricity and home heating all add to the costs of energy in the UK, making UK electricity prices among the highest in the world.
Articles
Information and Data
Questions
- Why are the UK’s energy prices among the highest in the world?
- What are the arguments for and against subsidising wind power?
- What is the Contracts for Difference scheme in low-carbon energy. What CfDs have been awarded? Assess the desirability of the scheme.
- Is the capping of gas and electricity prices the best way of providing support for low-income and vulnerable consumers?
- How are externalities relevant in determining the optimal pricing of electricity?
Africa’s energy transition is at a pivotal moment. While the continent boasts abundant renewable energy resources, its electricity generation and distribution remain fragmented. Cross-border electricity trade has emerged as a potential game-changer, fostering energy security, reducing costs, and accelerating the adoption of renewables. However, is Africa fully leveraging this opportunity?
In a forthcoming paper in the Energy & Environment journal, I join forces with my colleagues Mercy Adaji and Bereket Kebede to argue that the answer to this question is no. Our study examines the impact of cross-border electricity trade in renewable electricity generation across 21 African countries over a 24-year period (1996–2020). Our findings indicate that a 1% increase in electricity trade significantly raises the share of renewables in total electricity output by approximately 0.05%. This underscores the crucial role of regional integration in advancing Africa’s clean energy goals, aligning with previous studies (e.g., Boz et al., 2021; Song et al., 2022, linked below) that highlight how electricity market integration promotes renewable energy investments by stabilising supply and mitigating intermittency risks.
Despite these advantages, cross-border electricity trade remains significantly underutilised due to regulatory barriers, inadequate infrastructure, and governance challenges.
Net electricity-importing countries tend to benefit more from trade, while net-exporting nations, particularly those reliant on fossil fuels, exhibit weaker positive impacts. Without targeted policies (such as carbon pricing and green subsidies) trade disparities may persist, slowing the transition to clean energy.
Moreover, our results highlight the pivotal role of governance in fostering a robust electricity market. This is neither surprising nor new – quality of governance matters over the long term in all aspects of economic activity. Agostini et al. (2019), for instance, show that well-structured regulations and strategic investments in interconnections enhance the effectiveness of cross-border electricity trade. Transparent regulatory frameworks, expanded grid interconnections, and harmonised energy policies can significantly boost the impact of regional electricity trade.
By strengthening collaboration, African nations can mitigate energy poverty, enhance supply reliability, and accelerate the shift toward a greener future.
To capitalise fully on cross-border electricity trade, African policymakers must prioritise regional energy integration, invest in infrastructure and implement incentives to spur renewable energy expansion. With the right policies and co-operative strategies, Africa can harness its vast renewable potential and achieve a more sustainable, energy-secure future.
Articles
- Powering Africa’s sustainable future: The role of cross-border electricity trade on renewable electricity generation
Energy & Environment, Mercy Adaji, Nicholas Vasilakos and Bereket Kebede (17/2/25)
- A surplus based framework for cross-border electricity trade in South America
Energy Policy, Claudio A Agostini, Andrés M Guzmán, Shahriyar Nasirov and Carlos Silva (1/2/19)
- The effects of cross-border electricity trade on power production from different energy sources
The Electricity Journal, Deniz Ege Boz, Baris Sanli and M Hakan Berument (20/4/21)
- Energy market integration and renewable energy development: Evidence from the European Union countries
Journal of Environmental Management, Malin Song, Haitao Xu, Zhiyang Shen and Xiongfeng Pan (5/6/22)
Questions
- How does electricity trade help mitigate the intermittency challenges of renewable energy, and what mechanisms could further enhance its effectiveness?
- The study highlights governance quality as a crucial factor in the success of cross-border electricity trade. What governance-related challenges do African countries face in implementing a unified electricity market, and how can policymakers address them to maximize trade benefits?
- Our results show that net electricity-importing countries tend to gain more from trade than net-exporting ones, particularly those relying on fossil fuels. What policy measures can be introduced to ensure that net-exporting countries also benefit from electricity trade while advancing renewable energy integration?
- What are the most critical infrastructure and policy gaps that hinder the growth of cross-border electricity trade in Africa, and how can these be overcome to facilitate a more sustainable energy transition?
On the day he came to office, President Trump signed a series of executive orders. One of these was to set in motion the process of withdrawing from the UN Paris climate agreement. Section 3(a) of the order reads:
The United States Ambassador to the United Nations shall immediately submit formal written notification of the United States’ withdrawal from the Paris Agreement under the United Nations Framework Convention on Climate Change.
The Paris Agreement is an international treaty on climate change. It was adopted on 12 December 2015 and came into force on 4 November 2016, 30 days after the point was reached when at least 55 countries accounting for at least 55% of global emissions had ratified the treaty.
Currently, all UN countries are signatories to the agreement and only Iran, Libya and Yemen are yet to ratify it. The agreement commits countries to limiting global warming to well under 2°C above pre-industrial levels and preferably to no more than 1.5°C. This would involve reducing greenhouse gas emissions and/or taking carbon absorbing measures.
Since 2020, each country has been required to submit its own emission-reduction targets, known as ‘nationally determined contributions’ (NDCs), and the actions it will take to meet them. Every five years each country must submit a new NDC more ambitious than the last.
Rich countries are expected to provide finance to low-income countries. This is required to help poor countries adopt green technologies and to adapt to the harmful effects of climate change (e.g. through irrigation schemes and flood defences).
Countries set target dates by which emissions would be fully offset by carbon absorption measures (‘net zero’). The UN’s goal is to reach global net zero by 2050. According to the UN Climate Action site:
As of June 2024, 107 countries, responsible for approximately 82 per cent of global greenhouse gas emissions, had adopted net-zero pledges either in law, in a policy document such as an national climate action plan or a long-term strategy, or in an announcement by a high-level government official. More than 9000 companies, over 1000 cities, more than 1000 educational institutions, and over 600 financial institutions have joined the Race to Zero, pledging to take rigorous, immediate action to halve global emissions by 2030.
The Paris Agreement has helped to cut emissions or slow their rate of growth in most countries. Although net zero by 2050 may be unlikely, warming will be less than without the agreement.
The USA and the Paris Agreement
In April 2016 the USA signed the Paris Agreement. As stated above, the Paris Agreement came into effect on 4 November 2016.
President Trump came to office for the first time in January 2017. In June 2017, he signed an executive order in which he announced that the USA would withdraw from the agreement, arguing that it undermined the US economy and put it at a competitive disadvantage. He claimed that global warming is a hoax concocted by China designed to undermine the competitive power of the USA.
However, despite Trump’s intention to withdraw from the agreement, its terms did not allow a country to begin a withdrawal procedure for at least three years after the agreement was ratified (i.e. not before 4 November 2019) and then a year’s notice has to be given. This notice was given on 4 November 2019. In the meantime, the USA had to abide by the terms of the treaty. During this period, US representatives at COP meetings used the opportunity to promote fossil fuels. Withdrawal took place on 1 November 2020, just one day after the presidential election and just over two months before the end of Trump’s first term of office.
On 20 January 2021, his first day in office, President Biden signed an executive order to rejoin the agreement, which took place on 19 February 2021. He committed to cutting total greenhouse gas emissions by at least 50% by 2030. To achieve this, his administration adopted a number of emissions-reducing measures, for example requiring all new passenger vehicles sold after 2035 to be emissions free, giving tax credits for clean electricity generation, providing federal funds for smart agriculture and setting greener appliance and equipment standards.
But, as we have seen, newly elected President Trump for the second time announced that the USA would withdraw from the Paris agreement and would prioritise fossil fuel production, under the mantra, ‘drill, baby, drill’.
The economics of climate change
Climate change is directly caused by market failures. One of the most important of these is that the atmosphere is a common resource: it is not privately owned; it is a global ‘commons’. Individuals and firms use it at a zero price. If the price of any good or service to the user is zero, there is no incentive to economise on its use. Thus for the emitter there are no private costs of using the atmosphere in this way as a ‘dump’ for their emissions and, in a free market, no incentive to reduce the climate costs.
And yet when firms emit greenhouse gases into the atmosphere there are costs to other people. To the extent that they contribute to global warming, part of these costs will be borne by the residents of that country; but a large part will be borne by inhabitants of other countries.
These climate costs are external costs to the firm and are illustrated in the figure. It shows an industry that emits CO2. To keep the analysis simple, assume that it is a perfectly competitive industry with demand and supply given by curves D and S, which are equal to the marginal private benefits (MPB) and marginal private costs (MPC), respectively. There are no externalities on the demand side and hence MPB equals the marginal social cost (MSB). Market equilibrium is at point a, with output at Qpc and price at Ppc. (Click here for a PowerPoint.)
Assume that the emissions create a marginal cost to society equal to MECc. Assume that the MEC increases as output and total emissions increase. The MECc line is thus upward sloping. At the market price of Qpc, these external climate costs are equal to the purple vertical line. When these external climate costs are added to private costs, this gives a marginal social cost given by MSC = MPC + MECc. The gives a socially optimal level of output of the product of Q* at a price of P*, with the optimum point of c.
In other words, other things being equal, the free market overproduces products with climate externalities. If the output is to be reduced to the social optimum of Q*, then the government will need to take measures such as those advocated in the Paris Agreement. These could include imposing taxes on products, such as electricity generated by fossil fuels, or on the emissions themselves. Or green alternatives, such as wind power, could be subsidised.
Alternatively, regulations could be used to cap the production of products creating emissions, or caps on the emissions themselves could be imposed. Emissions permits could be issued or auctioned. Only firms in possession of the permits would be allowed to emit and the permits would cap emissions below free-market levels. These permits could be traded under a cap-and-trade scheme, such as the EU’s Emissions Trading Scheme. Again, such schemes are advocated under the Paris Agreement.
Effect of the USA’s withdrawal from the Paris Agreement
Withdrawal from the Paris Agreement and promoting fossil fuels will increase US emissions. Scientific consensus is that this will have a negative effect on climate change. Only part of these climate costs will be borne by the USA, although the severity of recent fires in California, fanned by strong Santa Ana winds, and more violent hurricanes are two examples of costs of climate change to the USA itself.
A bigger worry is whether the USA’s withdrawal will encourage other countries, such as Argentina, to do likewise. Then the climate costs of US withdrawal will be greater.
But all is not bad news. The transition to green energy is well advanced and the costs of solar and wind power are decreasing. Global investment in clean energy has increased by 60% since 2015. China is investing heavily in renewable energy technology, which is giving it a significant trade advantage. The EU has taken significant actions to promote green energy and technology. Similarly, industrial processes that economise on emissions are developing apace and it is becoming increasingly profitable for private companies to make climate-friendly investments without subsidies. In the USA itself, many Democratic states and local governments, and even some Republican ones, will continue to adopt climate-friendly policies.
In this environment, the Trump administration does not want to fall behind in the development of new technologies and markets. And with Elon Musk having a significant influence on Donald Trump, the USA’s investment in EVs and battery technology is likely to continue. This will help to reduce the price of green energy and transport.
Videos
Articles
- Trump vows to leave Paris climate agreement and ‘drill, baby, drill’
BBC News, Matt McGrath (20/1/25)
- What is the Paris climate agreement and why has Trump withdrawn?
BBC News, Esme Stallard and Mark Poynting (21/1/25)
- Six Trump executive orders to watch
BBC News (21/1/25)
- The real message behind Trump’s withdrawal of US from the Paris climate agreement
Sky News, Tom Clarke (21/1/25)
- Trump signs order to withdraw US from Paris climate agreement for second time
The Guardian, Dharna Noor (20/1/25)
- Explained: how Trump’s day one orders reveal a White House for big oi
The Guardian, Oliver Milman and Dharna Noor (22/1/25)
- Donald Trump can’t stop global climate action. If we stick together, it’s the US that will lose out
The Guardian, Bill Hare (6/11/24)
Trump to pull US from Paris climate agreement: What could this mean for the environment?ITV News, Martin Stew (21/1/25)
- 10 reasons why US president-elect Donald Trump can’t derail global climate action
The Conversation, Wesley Morgan and Ben Newell (8/11/24)
- Trump has rejected the Paris agreement again, but game theory shows how other countries can still lead by example
The Conversation, Renaud Foucart (27/1/25)
Information
Questions
- Summarise the Paris Agreement.
- Using a diagram similar to that above, illustrate how the free market will produce a sub-optimal amount of solar power because the marginal social benefit exceeds the marginal private benefit.
- How might game theory be used to analyse possible international decision making in the context of US climate policy?
- Is it in America’s interests to cease investing in green energy and green production methods?
- Go through each of the reasons (not specific to Australia) given in The Conversation article linked above why ‘Donald Trump can’t derail global climate action’. To what extent do you agree with each one?
In many countries, train fares at peak times are higher than at off-peak times. This is an example of third-degree price discrimination. Assuming that peak-time travellers generally have a lower price elasticity of demand, the policy allows train companies to increase revenue and profit.
If the sole purpose of ticket sales were to maximise profits, the policy would make sense. Assuming that higher peak-time fares were carefully set, although the number travelling would be somewhat reduced, this would be more than compensated for by the higher revenue per passenger.
But there are external benefits from train travel. Compared with travel by car, there are lower carbon emissions per person travelling. Also, train travel helps to reduce road congestion. To the extent that higher peak-time fares encourage people to travel by car instead, there will be resulting environmental and congestion externalities.
The Scottish experiment with abolishing higher peak-time fares
In October 2023, the Scottish government introduced a pilot scheme abolishing peak-time fares, so that tickets were the same price at any time of the day. The idea was to encourage people, especially commuters, to adopt more sustainable means of transport. Although the price elasticity of demand for commuting is very low, the hope was that the cross-price elasticity between cars and trains would be sufficiently high to encourage many people to switch from driving to taking the train.
One concern with scrapping peak-time fares is that trains would not have the capacity to cope with the extra passengers. Indeed, one of the arguments for higher peak-time fares is to smooth out the flow of passengers during the day, encouraging those with flexibility of when to travel to use the cheaper and less crowded off-peak trains.
This may well apply to certain parts of the UK, but in the case of Scotland it was felt that there would be the capacity to cope with the extra demand at peak time. Also, in a post-COVID world, with more people working flexibly, there was less need for many people to travel at peak times than previously.
Reinstatement of peak-time fares in Scotland
It was with some dismay, therefore, especially by commuters and environmentalists, when the Scottish government decided to end the pilot at the beginning of October 2024 and reinstate peak-time fares – in many cases at nearly double the off-peak rates. For example, the return fare between Glasgow and Edinburgh rose from £16.20 to £31.40 at peak times.
The Scottish government justified the decision by claiming that passenger numbers had risen by only 6.8%, when, to be self-financing, an increase of 10% would have been required. But this begs the question of whether it was necessary to be self-financing when the justification was partly environmental. Also, the 6.8% figure is based on a number of assumptions that could be challenged (see The Conversation article linked below). A longer pilot would have helped to clarify demand.
Other schemes
A number of countries have introduced schemes to encourage greater use of the railways or other forms of public transport. One of these is the flat fare for local journeys. Provided that this is lower than previously, it can encourage people to use public transport and leave their car at home. Also, its simplicity is also likely to be attractive to passengers. For example, in England bus fares are capped at £2. Currently, the scheme is set to run until 31 December 2024.
Another scheme is the subscription model, whereby people pay a flat fee per month (or week or year, or other time period) for train or bus travel or both. Germany, for example, has a flat-rate €49 per month ‘Deutschland-Ticket‘ (rising to €58 per month in January 2025). This ticket provides unlimited access to local and regional public transport in Germany, including trains, buses, trams, metros and ferries (but not long-distance trains). This zero marginal fare cost of a journey encourages passengers to use public transport. The only marginal costs they will face will be ancillary costs, such as getting to and from the train station or bus stop and having to travel at a specific time.
Articles
- Why a pilot scheme removing peak rail fares should have been allowed to go the distance
The Conversation, Rachel Scarfe (8/10/24)
- Return of peak rail fares a costly blow for commuters and climate, Scottish Greens say
Bright Green, Chris Jarvis (6/10/24)
- Commuters react to return of peak train fares in Scotland
BBC News (1/10/24)
- Perth peak rail fares to Edinburgh rise by almost 60 percent as pilot scheme ends
Daily Record, Alastair McNeill (4/10/24)
- Ditch peak-time rail fares across UK, campaigners say
iNews, Adam Forrest (30/9/24)
- Train fares reduced by up to 20% in East Yorkshire
Rail Advent, Roger Smith (26/9/24)
- Deutschland-Ticket: Germany’s popular monthly transport pass will soon be more expensive
Euronews, Angela Symons (24/9/24)
- Fare Britannia: a new approach to public transport ticketing for the UK
Greenpeace report, Leo Eyles, Tony Duckenfield and Jim Steer (19/9/24)
- Ministers urged to trial monthly ‘climate card’ in North of England to save rail commuters money and cut emissions
About Manchester, Nigel Barlow (20/9/24)
Questions
- Identify the arguments for and against having higher rail fares at peak times than at off-peak times
- Why might it be a good idea to scrap higher peak-time fares in some parts of a country but not in others?
- Provide a critique of the Scottish government’s arguments for reintroducing higher peak-time fares.
- With reference to The Conversation article, why is it difficult to determine the effect on demand of the Scottish pilot of scrapping peak-time fares?
- What are the arguments for and against the German scheme of having a €49 per month public transport pass for local and regional transport with no further cost per journey? Should it be extended to long-distance trains and coaches?
- In England there is a flat £2 single fare for buses. Would it be a good idea to make bus travel completely free?
Sustainability has become one of the most pressing issues facing society. Patterns of human production and consumption have become unsustainable. On the environmental front, climate change, land-use change, biodiversity loss and depletion of natural resource are destabilising the Earth’s eco-system.
Furthermore, data on poverty, hunger and lack of healthcare show that many people live below minimum social standards. This has led to greater emphasis being placed on sustainable development: ‘development that meets the needs of the present without compromising the ability of future generations to meet their own needs’ (The Brundtland Report, 1987: Ch.2, para. 1).
The financial system has an important role to play in channelling capital in a more sustainable way. Since current models of finance do not consider the welfare of future generations in investment decisions, sustainable finance has been developed to analyse how investment and lending decisions can manage the trade-off inherent in sustainable development: sacrificing return today to enhance the welfare of future generations.
However, some commentators argue that such trade-offs are not required. They suggest that investors can ‘do well by doing good’. In this blog, I will use ‘green’ bonds (debt instruments which finance projects or activities with positive environmental and social impacts) to explain the economics underpinning sustainable finance and show that doing good has a price that sustainable investors need to be prepared to pay.
I will analyse why investors might not be doing so and point to changes which may be required to ensure financial markets channel capital in a way consistent with sustainable development.
The growth of sustainable finance
Sustainable finance has grown rapidly over the past decade as concerns about climate change have intensified. A significant element of this growth has been in global debt markets.
Figure 1 illustrates the rapid growth in the issuance of sustainability-linked debt instruments since 2012. While issuance fell in 2022 due to concerns about rising inflation and interest rates reducing the real return of fixed-income debt securities, it rebounded in 2023 and is on course for record levels in 2024. (Click here for a PowerPoint.)
Green bonds are an asset class within sustainability-linked debt. Such bonds focus on financing projects or activities with positive environmental and social impacts. They are typically classified as ‘use-of-proceeds’ or asset-linked bonds, meaning that the proceeds raised from their issuance are earmarked for green projects, such as renewable energy, clean transportation, and sustainable agriculture. Such bonds should be attractive to investors who want a financial return but also want to finance investments with a positive environmental and/or social impact.
One common complaint from commentators and investors is the ‘greenium’ – the price premium investors pay for green bonds over conventional ones. This premium reduces the borrowing costs of the issuers (the ‘counterparties’) compared to those of conventional counterparties. This produces a yield advantage for issuers of green bonds (price and yield have a negative relationship), reducing their borrowing costs compared to issuers of conventional bonds.
An analysis by Amundi in 2023 using data from Bloomberg estimated that the average difference in yield in developed markets was –2.2 basis points (–0.022 percentage points) and the average in emerging markets was –5.6 basis points (–0.056 percentage points). Commentators and investors suggest that the premium is a scarcity issue and once there are sufficient green bonds, the premium over non-sustainable bonds should disappear.
However, from an economics perspective, such interpretations of the greenium ignore some fundamentals of economic valuation and the incentives and penalties through which financial markets will help facilitate more sustainable development. Without the price premium, investors could buy sustainable debt at the same price as unsustainable debt, earn the same financial return (yield) but also achieve environmental and social benefits for future generations too. Re-read that sentence and if it sounds too good to be true, it’s because it is too good to be true.
‘There is no such thing as a free lunch’
In theory, markets are institutional arrangements where demand and supply decisions produce price signals which show where resources are used most productively. Financial markets involve the allocation of financial capital. Traditional economic models of finance ignore sustainability when appraising investment decisions around the allocation of capital. Consequently, such allocations do not tend to be consistent with sustainable development.
In contrast, economic models of sustainable finance do incorporate such impacts of investment decisions and they will be reflected in the valuation, and hence pricing, of financial instruments. Investors, responding to the pricing signals will reallocate capital in a more sustainable manner.
Let’s trace the process. In models of sustainable finance, financial instruments such as green bonds funding investments with positive environmental impacts (such as renewable energy) should be valued more, while instruments funding investments with negative environmental impacts (such as fossil fuels) should be valued less. The prices of the green bonds financing renewable energy projects should rise while the prices of conventional bonds financing fossil-fuel companies should fall.
As this happens, the yield on the green bonds falls, lowering the cost of capital for renewable-energy projects, while yields on the bonds financing fossil-fuel projects rise, ceteris paribus. As with any market, these differential prices act as signals as to where resources should be allocated. In this case, the signals should result in an allocation consistent with sustainable development.
The fundamental point in this economic valuation is that sustainable investors should accept a trade-off. They should pay a premium and receive a lower rate of financial return (yield) for green bonds compared to conventional ones. The difference in price (the greenium), and hence yield, represents the return investors are prepared to sacrifice to improve future generations’ welfare. Investors cannot expect to have the additional welfare benefit for future generations reflected in the return they receive today. That would be double counting. The benefit will accrue to future generations.
A neat way to trace the sacrifice sustainable investors are prepared to make in order to enhance the welfare of future generations is to plot the differences in yields between green bonds and their comparable conventional counterparts. The German government has issued a series of ‘twin’ bonds in recent years. These twins are identical in every respect (coupon, face value, credit risk) except that the proceeds from one will be used for ‘green’ projects only.
Figure 2 shows the difference in yields on a ‘green bond’ and its conventional counterpart, both maturing on 15/8/2050, between June 2021 and July 2024. The yield on the green bond is lower – on average about 2.2 basis points (0.022 percentage points) over the period. This represents the sacrifice in financial return that investors are prepared to trade off for higher environmental and social welfare in the future. (Click here for a PowerPoint.)
The yield spread fluctuates through time, reflecting changing perceptions of environmental concerns and hence the changing value that sustainable investors attach to future generations. The spread tends to widen when there are heightened environmental concerns and to narrow when such concerns are not in the news. For example, the spread on the twin German bonds reached a maximum of 0.045 percentage points in November 2021. This coincided with the 26th UN Climate Change Conference of the Parties (COP26) in Glasgow. The spread has narrowed significantly since early 2022 as rising interest rates and falling real rates of return on bonds in the near-term seem to have dominated investors’ concerns.
These data suggest that, rather than being too large, the greeniums are too small. The spreads suggest that markets in debt instruments do not seem to attach much value to future generations. The valuation, price and yield of green bonds are not significantly different from their conventional counterparts. This narrow gap indicates insufficient reward for better sustainability impact and little penalty for worse sustainability impact.
This pattern is repeated across financial markets and does not seem to be stimulating the necessary investment to achieve sustainable development. An estimate of the scale of the deficit in green financing is provided by Bloomberg NEF (2024). While global spending on the green energy transition reached $1.8 trillion in 2023, Bloomberg estimates that $4.8 trillion needs to be invested every year for the remainder of this decade if the world is to remain on track under the ‘net zero’ scenario. Investors do not seem to be prepared to accept the trade-off needed to provide the necessary funds.
Can financial markets deliver sustainable development?
Ultimately, the hope is that all financial instruments will be sustainable. In order to achieve that, access to finance would require all investors to incorporate the welfare of future generations in their investment decisions and accept sacrificing sufficient short-term financial return to ensure long-term sustainable development. Unfortunately, the pricing of green bonds suggests that investors are not prepared to accept the trade-off. This restricts the ability of financial markets to deliver an allocation of resources consistent with sustainable development.
There are several reasons why financial markets may not be valuing the welfare of future generations fully.
- Bounded rationality means that it is difficult for sustainable investors to assign precise values to future and distant benefits.
- There are no standardised sustainability metrics available. This produces great uncertainty in the valuation of future welfare.
- Investors also exhibit cognitive biases, which means they may not value the welfare of future generations properly. These include present bias (favouring immediate rewards) and hyperbolic discounting (valuing the near future more than the distant future).
- Economic models of financial valuation use discount rates to assess the value of future benefits. Higher discount rates reduce the perceived value of benefits occurring in the distant future. As a result, long-term impacts (such as environmental conservation) may be undervalued.
- There may be large numbers of investors who are only interested in financial returns and so do not consider the welfare of future generations in their investment decisions.
Consequently, investors need to be educated about the extent of trade-offs required to achieve the necessary investments in sustainable development. Furthermore, practical models which better reflect the welfare of future generations in investment decisions need to be employed. However, challenges persist in fully accounting for future generations and it may need regulatory frameworks to provide appropriate incentives for effective sustainable investment.
Articles
- The fallacy of ESG investing
Financial Times, Robert Armstrong (23/10/20)
- Energy Transition Investment Trends 2024: Executive Summary
BloombergNEF (30/1/24)
- ESG metrics trip up factor investors
Financial Times, Emma Boyde (1/11/21)
- Our Common Future: Report of the World Commission on Environment and Development
United Nations, Gro Harlem Brundtland (chair) (20/3/87)
- Who killed the ESG party?
FT Film, Daniel Garrahan (17/7/24)
- Green bond issuance surges as investors hunt for yield
Financial Times, Lee Harris (19/6/24)
- Investing for long-term value creation
Journal of Sustainable Finance & Investment, 9(4), Dirk Schoenmaker and Willem Schramade (19/6/19)
- Facts and Fantasies about the Green Bond Premium
Amundi working paper 102-2020, Mohamed Ben Slimane, Dany Da Fonseca and Vivek Mahtani (December 2020)
- Climate change and growth
Industrial and Corporate Change, 32 (2), 2023, Nicholas Stern and Joseph E Stiglitz (30/7/24)
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Data
Questions
- Using demand and supply analysis, illustrate and explain the impact of sustainable investing on the markets for (i) green bonds and (ii) conventional bonds. Highlight how this should produce an allocation of finance capital consistent with sustainable development.
- Research the yields on the twin bonds issued by Germany since this blog was published. Can you identify any association between heightened environmental concerns and the spread between the ‘green’ and conventional bond?
- Analyse the issues which prevent financial markets from producing the pricing signals which produce an allocation of resources consistent with sustainable development.
- Research some potential regulatory policies which may provide appropriate incentives for sustainable investment.