/29th June 2017, IEA, RENEWABLE MARKET WATCHTM,IRENA/, The share of renewables in overall power generation is rapidly increasing, both in developed and developing countries. Furthermore, many countries have ambitious targets to transform their power sector towards renewables. To achieve these objectives, the structure and operation of existing power grid infrastructures will need to be revisited as the share of renewable power generation increases. Renewable energy technologies can be divided into two categories: dispatchable (i.e.biomass, concentrated solar power with storage, geothermal power and hydro) and non-dispatchable, also known as Variable Renewable Energy or VRE (i.e.ocean power, solar photovoltaics and wind).
The difficulty (or ease) of increasing the share of variable generation in a power system depends on the interaction of two main factors:
1) First, the properties of wind and solar PV generation; these include the constraints that weather and daylight patterns have on where and when they can generate. It is also relevant that VRE power plants are often smaller in scale than conventional generation and deployed in a more dispersed fashion. Finally, VRE connects to the grid using power converter technologies, which are different from conventional generators and lead to important integration effects.
2) Second, the flexibility of the power system into which VRE is integrated, the characteristics of the system’s electricity demand and climatic conditions. For example it is easier to integrate large shares of VRE where there is a good match with demand, and solar PV show less seasonal fluctuation in countries that have constant daylight hours during the entire year.
Flexibility is defined as the ability of a power system to respond to rapid swings in the supply demand balance, expected or otherwise. It can be provided by four fundamental resources: demand-side resources, electricity storage, grid infrastructure and flexible generation.
Policy, market and regulatory frameworks have a critical impact on the way in which these two factors interact. The frameworks determine how the power system is actually operated and hence whether what is technically possible is both practically achievable and economically attractive for stakeholders in the electricity system.
The interaction between the two factors differs from system to system as a result of technical variation as well as the influence of policy and market frameworks. However, a growing body of experience across a diverse range of power systems shows a common pattern of challenges. This allows for the development of best practice principles for policy and market frameworks –principles that can be applied in a wide range of circumstances.
In this context, advanced VRE technologies and deployment strategies can make a valuable contribution. Indeed, a VRE power plant is not simply a wind turbine or a collection of solar panels. Modern VRE plants connect to the grid using electronic power converters, so-called inverters. Simply put, these can be programmed like a computer to allow the way in which VRE power plants behave on the power grid to be controlled.
More information about integration of variable renewable energy integration you may read here: Europe Net Metering and Self-Consumption Solar PV Market Outlook 2016 - 2025