Conventional wisdoms on the superiority
of unfettered energy markets, and their ability to incentivise investment and
deliver reliable electricity supplies, are coming under challenge as never
before. The failure to deal adequately with the social costs and externalities
of CO2 emissions is one massive market failure, but even the
resolution of that through carbon pricing does not address the
structural flaw in many wholesale electricity markets. The policy imperatives for a low carbon economy are reinforcing many of
these structural failures, but the seeds of trouble have been there for some
time. The UK, in many respects the pioneer of market liberalisation, the EU
which has since adopted these ideas with enthusiasm, and New Zealand, whose natural
resource endowment (hydro) has allowed it to move a long way towards a low
carbon power sector, present different issues, but all are forced to confront
the same basic paradoxes in electricity economics. Failure to resolve these
will ultimately threaten security of supplies, and the credibility of national regulatory
frameworks.
Tariffs, pricing
and markets underpin both efficient resource allocation and the basis for power
sector investment, and have always deserved theoretical and practical
analysis. But there are two separate
objectives. One is a set of market prices that incentivises investment. The
other is market signals that ensure the efficient use of an existing stock of
generation capacity. The fundamental dichotomy is the distinction between the short
term and long term. The cost signals essential for production efficiency from
existing assets relate only to short run marginal costs (SRMC), but adequate
returns to investment, and to a significant degree retail tariffs, require prices
that cover total costs[1] including capital costs.
This is often described as long run marginal cost (LRMC). Both objectives matter. But it is the more limited SRMC, often equated
to the short term variable costs of fuel, that has become the key to most
wholesale markets, and in many ways the cornerstone on which liberalised market
structures rest.
Wholesale prices
based on SRMC are an outcome of the requirements for operational
efficiency. But it is intrinsic to SRMC
pricing that it is not sufficient to reward investment; nor will it signal to
consumers the full real costs of consumption which must include
investment. Allocative efficiency matters
in the consumption of electricity as well as in production; and in the wider
economy more cost reflective pricing for power will in principle reduce costs
and improve economic efficiency. For
both these reasons, the conceptual basis for electricity tariffs has often been
defined as LRMC, giving substantially higher prices that can cover investment
and other fixed costs. The structure of consumer tariffs can however
incorporate both SRMC and LRMC elements.
The UK 1990 model. When the institutional norms for the
power sector changed towards liberalised market structures, the LRMC/SRMC issue
was brought into sharp focus. “Energy
only” markets necessarily tend towards SRMC based outcomes, especially in
periods of surplus capacity. This does not cover investment costs or
incentivise new capacity investment[2]. In consequence some market designs have
attempted, explicitly or implicitly, to build in features which will, at least
in principle and over the long term, be capable of rewarding investment through
a spot price alone. A prime example was the England and Wales pool introduced
in 1990, using an administrative mechanism to define value of lost load (VOLL),
and loss of load probability (LOLP), to provide prices which spiked
dramatically. In principle at least this provided incentives for investment on
the basis of long term price expectations.
The approach was
essentially a clever attempt to reconcile SRMC and LRMC through a device which
purports to act as a surrogate for the “market” in assigning a scarcity value
to form part of a single “spot price”, albeit done by administrative means.
However this approach proved hard to maintain in a regulatory context, partly
because it implies and requires the possibility of very substantial price
spikes, some of which must be expected to persist over long periods if they are
to provide adequate returns on capital. However even this model, with a single “spot”
price, depended on an administrative intervention, external to the market, to
set VOLL and measure LOLP. This in turn reflects a political or administrative
view of the level of security or generation adequacy to which the system should
operate.
Post liberalisation experience.
This central intervention was one of the features that made the 1990
model unpopular and led, in the UK, to the NETA/BETTA reforms. Implicit in the
latter was the assumption that the market itself would somehow define an appropriate
level of security. The outcome was neatly summarised by John Kay in the FT.
“But
privatisation failed to provide a stable framework for planning new electricity
generation. The initial regime reflected careful thought about appropriate
incentives for capacity installation, but this regime was swept away in 2001 in
favour of a simpler one modelled on other commodity markets and known as NETA
(New Electricity Trading Arrangements), subsequently to be Betta (British
Electricity Trading and Transmission Arrangements). As so often in commodity
markets, this structure worked rather better in the short run than over the
long term.”[3]
A return to central
purchasing. Predictably the UK is now widely seen as
facing very tight capacity margins and the possibility of a supply crisis. In
response it has reverted to what is essentially a central purchasing regime
through the introduction of a capacity market. This is an entirely rational
response but it represents a major step away from the unfettered market philosophy
that underpinned the original power sector reforms, and the first step to a
centrally directed system. The challenge will be to ensure that this new
function for government is conducted efficiently and effectively.
EU ambitions for energy only markets. The EU has generally opposed the idea
of capacity markets, perhaps partly on ideological grounds, but more
convincingly because national capacity markets are potentially a major barrier
to a “single market” in electricity. The power sector has always been a
national not an EU responsibility, so national capacity markets are a further
barrier to integration. Importantly a single market that includes capacity can
only make sense if there is a single security standard across the system. This
would need to be set centrally and applied in all EU countries participating in
the single electricity market. It seems unlikely that the German government,
for example, would be happy to see such a fundamental choice made in Brussels.
Will regulators allow price spikes? New
Zealand experience. A necessary (but not sufficient)
condition for a market to be effective in inducing investment is that the
political and regulatory framework can allow for major price spikes in which
the only constraint on prices is the willingness of someone to pay. General
experience is that this does not happen. New Zealand was brought to my
attention this week, and is interesting because of the high proportion of zero
marginal cost generation. As such it presents a foretaste of how this market
question might play out in other jurisdictions, as the advent of low carbon
technologies accentuates the gap between SRMC and LRMC, with SRMC falling to a
very low [4] or zero level, while LRMC,
ie the full cost of supplying power, rises. The story, for market enthusiasts,
is not encouraging.
Price spikes do
occur and are subject to regular complaints of an “undesirable trading situation”, allowing the regulatory authority to
intervene and remedy the problem. So the natural “market” development of supply
shortages, inducing higher prices to bring forward additional supply or curtail
demand, is heavily constrained.
Prima facie
this should make life difficult for the generation utilities. However most are
vertically integrated into retail supply, and there have also been complaints
about the margins prevailing in retail supply. If correct this suggests that any
damage to the financial viability of generation is offset at least in part by
the ability to sustain excessive margins in another part of the business, a
situation that would be strongly redolent of complaints made about UK energy
utilities.
Ideology. In both New Zealand and the UK, there is
substantial tension between “energy only” free market enthusiasts and the
development of centrally directed capacity markets. Central purchasing has
entered the UK by stealth under Conservative or Conservative led coalition
governments. In New Zealand the left of centre Labour and Greens proposed a
central buyer model, only to be accused of Soviet-style economic vandalism.
We can expect
these controversies to continue and to accelerate as the world moves further
towards a low carbon, zero marginal cost world. But it is more and more evident
that conventional assumptions about electricity wholesale markets are no longer
“fit for purpose” and we shall in due course see further rounds of major
reform.
The Oxford Martin School Programme on the Integration of Renewable Energy will be returning to these and other questions, not just for the UK but in a wider international context.
[1] To be wholly accurate, we should distinguish actual
total costs from the concept of long run marginal cost, but for the purposes of
this particular exposition the distinction need not concern us very much.
[2] This
is most easy to demonstrate for peaking plant, which can only earn enough to
cover its fuel cost even in the very few hours when it runs. But a similar
revenue shortfall will apply to almost all plant to some degree.
[3] John
Kay. FT.
July 2013.
[4]
CCS, if it is ever built, might provide an exception to this.