The heat is on

IEA’s senior renewable energy analyst Milou Beerepoot tells Stephen Dineen about the possibilities from renewable co-generation and current debates on energy policy.

For Milou Beerepoot of the International Energy Agency (IEA), to mitigate the effects of climate change “we need a lot of different types of technologies, there’s not just one golden bullet.” In the IEA’s ‘Energy Technology Perspective’ 2011, renewable energy was envisaged as providing only 17 per cent of the CO2 emissions reductions required by 2050 to keep temperature increases below two degrees.

The technology occupying Beerepoot’s attention most is a synergy of more efficient power generation and renewables: renewable co-generation. With IEA research finding that fossil-fuelled power generation averages 35-37 per cent efficiency, it is a no-brainer.

“So what co-generation can do,” she states, “is increase the efficiency of power generation, and when you look at co-generation in combination with renewable energy, then you can realise a double carbon effect.” A low-carbon source is used whilst also utilising heat losses.

Increased use of renewables in electricity, of course, means variable electricity generation. Though gas is the conventional back-up generation Beerepoot points out that, unlike gas, renewable co-generation is a low carbon emitter.

The IEA renewables analyst cites three forms of renewable co-generation:

• biomass technology, which can be sourced through a range of sources such as agricultural waste, the paper industry and municipal waste;

• geothermal co-generation, which is not confined to countries with well-known geothermal resources (i.e. Iceland) but is being used in places with modest resources like Germany; and

• solar co-generation, which, while limited to regions with good direct solar resources, can have specific applications such as desalination and industrial process heat.

Denmark, known for its high penetration of wind energy on the system (and large electricity price fluctuations), also has numerous CHP plants and an elaborate district heating network. Electric boilers have also been rolled out. The country has discovered possibilities to use district heat and heat storages as a source of “storage for variable electricity”.

Beerepoot explains: “So what happens is that whenever the electricity prices are high the Danish district heating operator will use its co-generation unit to produce power where it can earn money and to produce heat for its district heat system.” When prices go down (due to high wind penetration), electric heat boilers are used to produce heat for storage.

The result is “a kind of hybrid system where the heat they need is either produced with the co-generation unit or it is produced from electricity whenever there is a surplus of electricity.” This helps balance the variable levels of electricity whilst interconnecting the heat and electricity systems. When prices are very low, in some parts of the country, electric heat pumps produce heat with electricity.

Beerepoot believes that the hybrid system could be replicated in other environments: “You could perhaps even think of hybrid systems on a residential scale as well, where you either choose to burn gas if the electricity price is high, or you choose to use electricity for heat whenever the electricity price is very low.” It could be used on a small scale “where of course there is also a lot of heat boilers.”

Linking electricity and heat systems, she cautions, means “you need to look at heat demand, heat planning,” to make the heat by-product useful.

For Beerepoot, who is contributing author to the renewable heat chapter of the IEA’s annual ‘World Energy Outlook’, such innovation must be at the heart of smart energy systems, “to absorb the variable electricity.”

The relevance of linking heat with renewable power generation, according to Beerepoot, is the high proportion of heat in final energy use and its carbon sources.

In 2009, heat constituted 47 per cent of global energy use and 43 per cent in Ireland. Heat is not just used for buildings, but also in industrial use:

44 per cent of heat use globally in 2009, 29 per cent in Ireland.

Also in 2009, gas accounted for 27.1 per cent of global heat use and accounted for 32.1 per cent in Ireland. Petroleum sourced 19.3 per cent of heat globally and 52.6 per cent in Ireland.

In Northern Ireland, Energy Minister Arlene Foster introduced a renewable heat premium payment scheme in May to support the installation costs of such heating systems in households. A renewable heat incentive (tariff) for the commercial sector is expected to commence this autumn, extended to households in 2013.

Warm climate countries use energy for heat in considerable proportions, Beerepoot adds, not just cold climate countries. She gives the examples of Indonesia (65 per cent of energy use was heat) and China (62 per cent) in 2009.

Global shifts

At present, Beerepoot observes debates on renewables targets and price supports. In Germany, for example, “they want to phase out their nuclear power and they want to move towards much higher penetrations of renewable energy.” This will be challenging “since at the same time they want to reduce their support levels for renewable electricity.”

She states: “We do know that we need supports [for renewables] still, now, in order to make the costs go down in time.” An example of subsidies decreasing after driving down prices is those for photovoltaics. “So that is a continuous discussion, when to reduce the support level but still keep it a stable policy scheme,” she states, “and those are the questions that many governments are now faced with.”

The IEA, she says, now sees non-members recognising “the importance of looking into renewable energy, not from a climate perspective, but just because they see their need for energy growing so fast”. They are looking to renewables simply to meet demand. The agency is experiencing “good collaboration” on numerous renewable projects with the BRIC countries.

Closer to home, EU countries are taking their 2020 targets seriously. “But I guess that not too long from now we should already look beyond 2020,” she states. Some countries have started doing this, Beerepoot says, citing Germany and its “very ambitious targets”. By 2050, it wants 80 per cent of electricity to be renewable, along with 60 per cent of its energy.

Germany may be powering ahead, but other countries need to do more. Beerepoot says that in the current economic climate countries are finding it harder to “keep going strong in that field with so many other conflicts asking for attention.”