No more bubbles - the decarbonated grid

The accelerated penetration of renewable resources is resulting in grid security and plant operational issues. These will require innovative solutions and extraordinary cooperative efforts from all industry role players.
Published: Wed 25 Sep 2013

Currently, the biggest issue for renewable energy is its efficient and reliable integration with the power grid. As policies support the increase in renewable generation, a number of challenges are brought to the table. Not least of which is the velocity of new energy technologies coming online, including electric vehicles, energy storage, efficient buildings that cut power use during peak times, and small-scale natural-gas generators and fuel cells. Integrating these technologies on a large scale presents a significant challenge.

Another stumbling block is an inadequate regulatory structure. Without this, the regulatory landscape for market rules and renewable policies can be fractured and complex. This makes the integration of renewables very challenging. Unclear rules and targets for renewables integration can result in a slower adoption, at a higher cost. The electrical energy storage industry faces similar obstacles: see Engerati’s Energy Storage: Can It Ever Happen?

While regulation should incentivize the development of new transmission and generation technologies required to fully enable large-scale renewable generation, it is also essential to support their integration.

Smart grid technology offers one approach to successful integration but there are additional methods that will assist integration and new areas with require fresh thinking and attention.

Cybersecurity

The complex technology layer needed to facilitate a bi directional and operationally lean grid  requires new thinking on how the security fabric is laid out. This was discussed extensively in a recent Engerati Insight webinar with McAfee and Intel looking at Sentient Cybersecurity. The key point addressed was how you build a aware security fabric which supports the implimentation of pervasive command and control layer needed for todays bi directional grid.

Electricity Storage

Without economically viable, large-scale storage, the grid relies heavily on the flexible operation of thermal generation units such as coal, natural gas and nuclear generation. However, the ability of these plants to operate in a flexible manner can be limited by both physical plant and financial constraints. Prioritizing grid access to renewables may prove unhelpful if it means undermining the economics of coal, gas and nuclear to the point that those conventional energy sources are unprofitable. Energy storage also has the ability to smooth variability.

Build more transmission capacity

The right bulk transmission capacity is essential for large-scale renewable generation: see Germanys Energiewende is Destabilizing the Grid. If utilities are to make use of vast renewable power potential in often remote locations, they must be able to transmit it efficiently from its production point to cities and load centers.

Increased Demand Response

Demand response technology will help operators to manage demand fluctuating outputs. By ramping up demand at facilities during peak supply periods and decreasing demand when supply drops off, the grid is able to respond to changing conditions in real time- without the need for storage.

Grid Flexibility

Flexibility refers to the grid’s ability to run smoothly despite fluctuations in generation and demand-planned or unexpected. Flexibility of the grid must be enhanced to support significant amounts of variable renewable energy generation. Improved flexibility will help operators to maintain the required balance between electricity supply and demand, even at high levels of variable renewable generation on the grid. Better flexibility can be achieved by developing an energy portfolio that contains a range of options on both the demand and supply sides.

A demand-side option, for example, may involve the use of more-responsive loads, such as air-conditioning systems that can be switched off automatically by the power provider during times of excessive peak demand.

The supply side can encourage flexibility in several ways, as well. These include flexible conventional generation, grid storage, and new transmission infrastructure—all of which are aspects of improved energy systems integration. Natural gas and renewables can be collaborative, rather than competitive. In particular, power plants fired by natural gas, rather than coal, can handle the more frequent and sometimes faster ramping that may be needed to balance the variable generation of renewable technologies.

Data mashups - Better forecasting

Improved forecasting of solar and wind resources can help operators better handle uncertainty when scheduling generation options. The aim is for forecasting to become so accurate that utilities are able to reduce generation at coal-fired plants. When renewable energy plant operators can predict generation ahead of time, the plants will operate like traditional generation sources such as coal, hydropower, and nuclear plants. This will make wind and solar integration on the grid much easier.

Bigger Pools

Balancing pools can continually match generation to demand balancing generation and load in real time leading to a more stable power system. Conventional generating plants will provide the balance assisted by relevant short and long term energy storage facilities.

Bigger pools will be most effective at balancing variable generation resources which will encourage a greater use of renewable energy. With a larger pool, geographically distributed renewables and more “stable” conventional generating plants will provide more certainty that demand can be met if output at some renewable energy plants is low. It will also provide a bigger market for the high production of clean energy. As a result, there will be fewer curtailments of wind and solar plants.

Power Factor Correction

Power factor correction helps to maintain grid stability. This affects both wind and solar sites where turbine and inverter technologies are starting to integrate reactive power correction capabilities to meet this requirement. However, these capabilities may be insufficient. if Independent System Operators (ISOs) move toward fully dynamic reactive compensation requirements, there may be a need for reactive compensation systems within the plant’s interconnection substation. This can be seen in Texas’ ERCOT ISO and their latest variable generation interconnection requirements. Existing plants will also need to find solutions to comply with these requirements.

Research

Research centers such as the Energy Systems Integration Facility (ESIF) in the US will help resolve a number of challenges that renewables integration face. Launched by the US Department of Energy’s National Renewable Energy Laboratory (NREL), the facility is dedicated to researching the integration of clean energy technology to the grid at utility-scale. The facility has multiple capabilities which will be used to solve integration challenges surrounding electricity generation, transmission, and grid operation.

Engerati Analysis

The journey towards a true smart grid, dominated by clean energy, will not be smooth as traditional infrastructure and business models face significant change. However, without the appropriate governmental and financial backing, following through on solutions may prove difficult.

Sources

CleanTechnica-Breakthrough NREL Lab Could Solve Renewables-Grid Integration Problems

Grid Talk-Three Ways that Renewable Integration is Changing the Grid

Intelligent Utility-MIT:The challenge of integrating renewables

MIT Technology Review-A Sneak Peek of the National Grid on Renewables

Reuters-EU law unclear on integrating renewable power:Wynn

Technology Review-A Sneek Peak of the National Grid on Renewables

The Energy Collective-How Hard is it to Integrate Renewable Energy into the Electric Grid?