Renewable Energy Integrated Power Supply Systems ...

Paper prepared for the IEA Bioenergy Task 29 Workshop in Alberta, Canada, 28-31 May 2001

Renewable Energy Integrated Power Supply Systems for Rural Communities Phil Murray and Ralph E. H. Sims Centre for Energy Research, Massey University Private bag 11222, Palmerston North, New Zealand Tel: +64 6 3505288 Fax:+64 6 3505604 [email protected]

Rural communities of New Zealand may have their electricity supplies and services cut in the future. The Electricity Act 1992 states that existing power lines must be maintained until 2013 but after this their fate depends upon the profit motives of the new and commercially orientated lines companies. An opportunity exists for rural communities to generate their own power using local renewable energy resources such as forest residues and sell excess power to the wholesale electricity market. Relevant to this are rapidly developing small scale bioenergy generation technologies; the global trend towards distributed electricity generation; New Zealand’s commitments to climate change and carbon emissions trading; power quality, controls and supply reliability; and the pending legislation changes which will encourage small scale embedded generation. Worldwide, there are evident trends towards renewable energy based, distributed generation systems for rural communities. The benefits include retention of the existing customer base, expansion of supply to outlying areas, additional revenue from renewable energy certificate trading, and increasing the efficiency of the network as a whole, especially where existing power line capacity will require upgrading to match increasing loads. Rapid commercial developments in fuel cells, Stirling engines, micro-turbines etc will also provide future opportunity for locally produced bioenergy fuel sources to be utilised from forest and agricultural residues and wastes. An on-going Massey University research programme has to date involved the monitoring of electricity demand loads in several rural communities and matching their seasonal and diurnal variations with local renewable energy resources. This programme has now reached an interesting phase. A systems approach is to be developed using decision analysis tools to optimise the design of a small scale (120MWe) embedded, renewable energy based, integrated power supply system. This will then be compared with other options such as the development of a similar, but independent system with a local mini-grid; selling or leasing standardised designs of independent domestic power supply systems to individual customers; repairing or upgrading existing lines as at present; or withdrawing supply services totally from non-commercially viable parts of the rural network. All the existing data and computer model outputs will be collated in order to develop a procedure for a rural community, lines company or energy service provider to be able to compare the range of business opportunities. Important issues that will be addressed by this next phase of the research will include: • the timeliness of investment in small distributed generation plants due to the changes in legislation; • the social cost and benefits of the changes and any greenhouse gas mitigating measures that can be identified and costed in; • the further development of empirical renewable energy resource assessment methods allowing for rapid and cost-effective feasibility studies of the renewable energy resources in a district; • the most appropriate generating technologies to reliably match the load requirements, including seasonal and daily peaks; • a new business approach for lines companies which could include the provision of a range of services to customers other than simply supplying power via a line network.

Paper prepared for the IEA Bioenergy Task 29 Workshop in Alberta, Canada, 28-31 May 2001 The overall aim is to develop a ranking methodology within a systems approach to find the optimum solution from a range of renewable energy based system solutions, which includes: • the repair or upgrade of the lines as needed and to pass the relevant costs to the consumers which is in effect the status quo; • the development of a renewable energy based distributed generation plant within a rural region, thus strengthening the immediate network voltage and reducing voltage fluctuation and energy losses within the network section involved, often towards the end of a long line; • design a standard modular reliable renewable energy based SAPS system which could be purchased and easily installed with the electricity sold to the local consumers as at present; or • a full withdrawal of services from non-viable parts of the distribution network. The objectives and rationale of this research can be defined as: • identification and determination of the effects of the impending changes to the rural electricity supply sector; • identification of potential rural electricity supply service providers; • identification of suitable renewable energy based methods of electricity provision; • consider biomass models as they relate to small scale heating and co-generation. • establishment of renewable energy based distributed generation site selection criteria, including economic parameters; • establishment of renewable energy resource assessment site selection criteria; • rural electricity load modelling; • identifying both the social cost of electricity supply issues; and • demand side management (DSM) implementation and effects. The five phases in the flow chart of Figure 1 are indicative of a potential system design and decision analysis within a systems approach framework. Phase 2a and 2b represent two parallel systems while phase 3 and 4 can be said to be systems in series with distinct inputs required before site selection decisions can be undertaken. The boxes outlined with green indicate the previous research work undertaken and the red outlined boxes indicate work to be undertaken as indicated by this proposal. The results of the research will produce a practical method to identify good investment opportunities for rural communities and line companies in renewable energy power generation and small rural generating schemes. ‘Fine-tuning’ aspects will be included to allow for flexibility of interpretation and application as circumstances change from region to region. Cost effective renewable energy resource assessment techniques in conjunction with a site selection procedure will attempt to minimise the cost of both pre-feasibility and feasibility analyses of renewable energy resources. A procedure to aid in the selection of generation options and sites will be developed utilising validated computer based models for analysis and design procedures based on a systems approach.

References Draft Energy Efficiency and Conservation Strategy, (2001). Making renewable energy efficiency and renewable energy mainstream solutions. EECA & MfE. Electricity Act 1992. New Zealand Government Legislation Electricity Industry Reform Act 1998. New Zealand Government Legislation. Energy Efficiency and Conservation Act, 2000. New Zealand Government Legislation. Irving, G. (2000). Community owned and operated Renewable Energy schemes in Rural New Zealand. MApplSci Thesis, Massey University, Palmerston North, New Zealand.

Paper prepared for the IEA Bioenergy Task 29 Workshop in Alberta, Canada, 28-31 May 2001

Phase 1

Potential clients

Potential dr ivers of change

- Rural consumers - Line companies - Other f unding agency

Legisla tion EA 1992 Legisla tion EIRA 1998 Legisla tion EECA 2000

Potential ser vice provider Servic e provid er can install either - SA PS system - Distributed generation - Line overhaul What sort of energy provider - Line company - Other f unding agencies

Energy requir ement - Inf rastructure inadequacie s

Em pir ical methodology of resour ce assessment w ithin a s ystem s appr oach Wind

Phase 2a

Met data - A necdotal - Local - Regional

Solar Solar modelling - Geometrical - Magnitude - A ccess - Utilisibility

Wind modelling - Terrain - Geostrophic

Hydro Met data - A necdotal - Local - Regional

Biomass Biomass modelling - Transport - Inf rastructure

Hydrologic al modelling

GIS - topogr aphical assessment

Load par ameters defined Modelling & simulation - design optimisation

Ef f iciency measures - ID and costings - Cost benef it analysis

Load estimators - Peak demand - Periodicity of peak demand - Base lo ad demand - Seasonal variations - Daily and hourly noise (SD, % etc)

Phase 2b

Socio-economic factors - Enhance productivity - Maintain status quo - A “necessity of life...”

Site Assessment of both load re quirem ents and energy resour ce availability

Phase 3

Site A - Wind - Solar - Hydro etc

Site 1 - 5 m/s - 4 kWh/m2 - 25 l/s - 20m

Site 2 - 8 m/s - 4 kWh/m2 - 45 l/s - 10m

Site 3 - 6 m/s - 4 kWh/m2 - 15 l/s - 5m

Ranked s ites based on cr iter ia to sor t ’le ast cost’ cus tomers to supply

Phase 4

Site A - Energy req’d - V ariation - Ef f icie ncy

Site 1 - Energy req’d - V ariation - Ef f icie ncy



Ranked s ites based on cr iter ia to assess best options for ener gy provider

Fina l Result

-

Site A Economic Social Environment Technological

-

Site 1 IRR 12% Status quo No damage Feasible

-

Site 2 IRR 5% Enhanced No damage Feasible

-

Site 3 IRR 4% Status quo Slight Feasible

Figure 1: Potential system design and decision analysis framework to assess the applicability of renewable energy based distributed generation systems or stand alone power supply systems. The long dash outlines indicate project work to be enacted and the– dash outlines indicate work from previous research undertaken at Massey University.