Our grid system can cope with home-grown renewable energy?

With more people wanting to be energy self sufficient and goverments providing financial incentives to make this ideal more affordable, we are looking at a future where domestic energy generation is rolled out to the masses.

In the UK, National Grid operate the high level grid infrastructure (generally any substations, power lines or cables rated at above 132kV) and distribution network organisations operate the local grid infrastructure of 132kV and below in the different regions.

With this anticipated increase in households generating their own green electricity, so will come increasing demands to connect these individual generators to the local distribution networks. Domestic generators such as solar PV panels, micro-wind turbines, or micro-scale CHP units will have the potential to export small amounts of electricity (as little as 0.5 kW). The result will be far more complex, actively managed local electricity networks, in which power flows in different directions at different times. Ensuring that distribution operators are ready for this change represents a major challenge.

Distribution operators will need to manage power coming onto its system from a potentially large number of small renewable energy suppliers who were once solely their customers. This is to some extent a ‘role reversal’ scenario from the past/ present situation where distribution operators buy electricity from few larger generators and supply to a large number of customers (a passive system).

The Electricity Networks Strategy Group (ENSG) provides a UK forum bringing together key stakeholders in electricity networks that work together to support government in meeting the long-term energy challenges of tackling climate change and ensuring secure energy.

The Group is jointly chaired by the Department of Energy and Climate Change (DECC) and Office of Gas and Electricity Markets (Ofgem) and its aim is to ‘identify, and co-ordinate work to help address key strategic issues that affect the transition of electricity networks to a low-carbon future’. Various workgroups have carried out case studies, produced best practice guidance and recommendations for the facilitation of micro-renewables. The group is now working on the development of smart grids (automated two-way communication on the grid by way of digital technology).

UK electricity regulator Ofgem said in its annual report last year that it wants distribution network operators to be “more in touch with the needs of their customers… not least because of the growing customer interest in managing their energy use, for example by installing rooftop wind turbines and other forms of microgeneration…this could lead to significant amounts of generation connecting directly to the distribution network rather than the national grid”. Despite all of this work it is not yet clear as to whether smart technology and new management systems will be ready in time for the anticipated domestic renewable energy rush, if indeed it does materialise.

Utility consultant Steve Piper recently reported on the issue in relation to the US grid network. Piper concluded that some areas of the country are experiencing increasing amounts of residential electricity generation, especially from solar PV. Even with the rapid installation of this distributed generation expected by the US’s National Renewable Energy Laboratory (NREL), it does not appear that it will approach limitations on electrical circuit capacity soon. However, the load and current restrictions may cause pinch-points in areas where interest in and subsidy of residential renewable energy generation is very high. At the same time work on how the electricity grid can be managed to optimise the use of residential renewable energy is in progress, and will likely be revised as utility experience with this distributed generation grows.

With no obligation to secure any form of consent to connect to a distribution operator’s network, and no clear idea of when the domestic renewable energy market will in reality take off, the strategy in both the UK and the US appears to be currently based very much on a ’suck it and see’ approach.