Electricity System Reform to Utilise Wind Turbine Potential

Hiroshi Hamasaki, Research Fellow
Amit Kanudia(*1), Partner, KanORS-EMR, NOIDA, India

May 22, 2013 (Wednesday)

1. Is it really possible to utilise all wind turbine potential?

According to the MOE’s “Renewable Potential Survey 2010,” Japan has 280 GW of potential on-shore wind energy. If we assume an average availability factor of 24%, this potential can generate 590 TWh of electricity annually. Given that in 2011, Japan’s 10 power companies sold 859.81 billion kWh2, on-shore wind has the potential to supply 70% of Japan’s power.

According to a report by the Cost Verification Committee (Dec 19, 2011), when model plants of each type of electricity generation were assigned and costs of generation calculated, on-shore generation was a competitive 8.8-17.3 yen/kWh when compared to coal (10.3 yen/kWh) and LNG thermal (10.9 yen/kWh). With the future of nuclear power being unclear, on-shore wind could play a large role in the future in terms of energy security and reducing greenhouse gas emissions.

There are several reasons why the actual availabilities may turn out lower and prices would turn out higher, than what is described above:

The Japanese electricity system comprises10 grids with weak inter-grid connections. The greatest potential for on-shore wind lies in the Hokkaido and Tohoku regions in the north, while the Kanto region has great demand but limited potential, resulting in geographical supply-demand mismatch. Given the current state of Japan’s power grids, the full potential of on-shore wind in the north cannot be tapped. In order for electricity produced in the north to be consumed in Kanto, interconnecting facilities are necessary, which drives up the cost.

Electricity must be produced exactly when it is consumed. It (and heat, to a large extent) is different from other energy forms like oil and gas in that several hours or days of supply cannot be stored in tanks and cylinders at the point of consumption. Wind power generation depends on wind flows, which are reasonably stable when averaged over months and years, but actual flows over hours and days can be significantly higher or lower than these averages. To match the demand (with seasonal and diurnal variations) using an intermittent source we need a combination of standby capacity and storage. Standby capacity could be LNG that can respond quickly and meet the deficit when wind flows are low. Storage would absorb energy when flows are above average and release when they are below. Both these options increase the cost of supplying electricity.

In addition, competitions among renewables may also lower the actual utilisation of renewables below their potentials.

In this research, we explore interactions between penetration of wind power and the following factors: (1) inter-grid capacity expansion, (2) carbon capture and storage (CCS), (3) cheap solar and (4) electricity storage.

We assume that nuclear power is discontinued starting in 2013 in each of these scenarios. 10 levels of CO2 prices ($0 to $1,000/t-CO2) are used in each scenario, to trigger low-carbon configurations. The simulation is carried out from 2013 through to 2050.

2. Simulation Results & Analysis

1) The Impacts of Grid Expansion

As pointed out above, Japan’s current division of its power grid into 10 smaller grids with limited interconnection may have stunted the use of wind power potential, and this simulation supports that hypothesis. Expanding current grid interconnections would increase onshore wind deployment by 1.5 times.

Figure 1: Impacts of Grid Expansion on Wind Turbine Electricity Generation 

Note 1: green = with Grid Expansion; blue = without Grid Expansion
Note 2: horizontal axis = Onshore Wind (TWh); vertical axis = Offshore Wind (TWh)

2) The Impacts of Storage

It is expected that using electricity storage will increase utilisation of onshore wind turbines, whose power generation timing cannot be controlled. However, from our simulation results, using electricity storage will not lead to more utilisation of onshore wind. In other words, without grid expansion, the benefits of electricity storage on on-shore wind utilisation are limited. Electricity storage will boost the utilisation of off-shore wind turbine only after grid expansion is accomplished.

Figure 2: The Impacts of Storage on Wind Turbine Electricity Generation 

Note 1: green = with Storage; blue = without Storage
Note 2: horizontal axis = Onshore Wind (TWh); vertical axis = Offshore Wind (TWh)

3) The Impacts of CCS

Carbon Capture and Sequestration (CCS) is another popular strategy for reducing greenhouse gas emissions, but it does not greatly affect the spread of wind power. On the other hand, as carbon prices increase, CCS becomes competitive with offshore wind, since introduction of the former results in less penetration of the latter.

Figure 3: The Impacts of CCS on Wind Turbine Electricity Generation 

Note 1: green = CCS, blue = Non-CCS
Note 2: horizontal axis = Onshore Wind (TWh), vertical axis = Offshore Wind (TWh)

4) Benefits of GE and Storage on On-shore Wind

The figure below shows electricity generation of on-shore wind turbines in 2030 for each of 4 cases. Grid expansion results in a significant increase of on-shore wind turbines in Hokkaido and Tohoku. The figure also shows that the current Japanese electricity grid cannot fully utilise on-shore wind potential in Hokkaido and Tohoku.

Figure 4: Onshore Wind Generation by Region （2030）（TWh）

4. Creating an Environment to Realize Wind Potential

Japan’s 10 separate electricity grids limit the potential of wind power. This means that wind turbines are not built in highly cost-effective regions, and that even if partial optimization is being performed on each regional power grid, the entire system is not being optimized. This results in high costs for increasing the spread of renewables. Introducing electricity storage will not, unfortunately, solve this inefficient and disjointed system.

In order to solve the above issues, Japan must establish a Broad Electricity Grid Operator in order to increase the efficiency of the country’s entire electricity system. Not only would this increase the cost-effectiveness of introducing renewable energies, but it would also remove the need for individual power companies to be able to entirely fill demand and reduce the capacity necessary for providing stable supply. At the same time, interregional flexibility would increase and we would be able to avoid rolling blackouts like those experienced following the 3.11 earthquake.

Notes

(*1): Energy modelling researcher and consultant since 1993, has a Ph.D. in production and quantitative methods (operations research) from the Indian Institute of Management, Ahmedabad. He did his graduate studies at the Indian Institute of Technology, Kanpur, with specialization in mechanical engineering. His involvement in this field has been at diverse levels: methodological developments, setting-up of large models, using models for policy analysis and the design and development of sophisticated user interfaces. He has published more than 20 articles and monographs in refereed scientific journals in the area of energy-environment modeling and analysis. He has been the key technical resource in several projects involving setting up large multi-region TIMES and MARKAL models.

(*2): Investment and O&M cost will decrease by 50% in 2030 and 75% in 2050.

(*3): Unlimited availability of a $2,000/kW technology with storage EFF of 75% and charge/discharge rates suitable for day-night storage.

References

• Committee of Electricity Generation Cost Verification, National Policy Unit, Cabinet Secretariat, Japan (2011), Committee of Electricity Generation Cost Verification Report, 19th December, 2011.
• Ministry of the Environment (2011), Renewable Energy Potential Survey Report.
• IEA/NEA (2010), Projected Costs of Generating Electricity, 2010 Edition.
• National Institute of Environmental Studies (2011), Path Reviews of Japan Low-carbon Society –towards the realisation of CO2 80% reduction society,
  http://www.env.go.jp/council/06earth/y060-92/ref01-4.pdf
• Roney, J. Matthew (2011), Time to Rethink Japan’s Energy Future, April 07, 2011,
  http://www.earth-policy.org/plan_b_updates/2011/update94
• WWF Japan (2011), Energy Scenario Proposal towards Decarbonised Society, Final Report,
  http://www.wwf.or.jp/activities/upfiles/20111117EnergyScenario02.pdf
• Dale, Lewis, David Milborrow, Richard Slark and Goran Strabac (2004), Total Cost Estimates for Large-scale Wind Scenarios in UK, Energy Policy 32 (2004) Pages 1949-1956.
• Ibrahim, H., A. Ilinca and J. Perron (2008), Energy Storage Systems – Characteristics and Comparisons, Renewable and Sustainable Energy Reviews, Volume 12, Issue 5, June 2008, Pages 1221-1250.